Preparation method of high-purity aluminum-silicon-copper ingot for target material

Abstract

The present application relates to a kind of preparation methods of high-purity aluminum silicon copper ingot for target material, the preparation method includes the following steps: (1) aluminum raw material is melted, and aluminum liquid is obtained;(2) copper powder and silicon powder are loaded into aluminum foil bag, and powder bag is obtained, the powder bag is added to the aluminum liquid obtained in step (1), and aluminum silicon copper alloy liquid is obtained;(3) the aluminum silicon copper alloy liquid obtained in step (2) is sequentially degassed and is slagged, and purifying alloy liquid is obtained;(4) the purifying alloy liquid obtained in step (3) is sequentially cast and cooled, and the aluminum silicon copper ingot is obtained.The preparation method provided by the present application can fully promote the dispersion of aluminum silicon copper, improve the uniformity of composition, and shorten the smelting time, avoid the generation of hot crack and feather-like grain.

Description

Technical Field

[0001] This invention relates to the field of high-purity aluminum alloy smelting and casting, and specifically to a method for preparing high-purity aluminum-silicon-copper ingots for target materials. Background Technology

[0002] High-purity aluminum thin films possess advantages such as low resistivity, ease of deposition and etching, and mature processing technology, making them a primary conductive material for integrated circuits. Adding elements like Si and Cu to high-purity aluminum thin films can reduce electromigration and improve conductive performance. Aluminum thin films are formed by physical vapor deposition (PVD) using sputtering targets. The raw materials for sputtering targets are high-purity aluminum and high-purity aluminum alloy ingots, which are then smelted and cast from high-purity aluminum raw materials and alloys. Therefore, the compositional uniformity, microstructure, and internal defects of high-purity aluminum and high-purity aluminum alloy ingots directly determine the performance of the sputtering target. Especially with aluminum-silicon-copper ternary alloys, due to the large particle size of raw materials such as Si and Cu, which easily deposit at the bottom of the furnace, the smelting time is long and compositional uniformity is difficult to control. This leads to abnormalities such as segregation, hot cracking, and feather-like grains in aluminum-silicon-copper ingots.

[0003] CN101812590A discloses a method for producing aluminum-silicon-copper alloy using an electrothermal method. This method utilizes coal-based kaolin and copper oxide as raw materials, and petroleum coke and bituminous coal as reducing agents. The process involves sequential steps including raw material pretreatment, batching, pelletizing, and electrothermal preparation of the aluminum-silicon-copper alloy. However, the purity of the aluminum-silicon-copper alloy obtained by this method is not high, making it difficult to meet the requirements for high-purity sputtering targets.

[0004] CN107012345A discloses a method for preparing an aluminum-silicon-copper alloy. This method involves first melting molten aluminum and pure copper to obtain an aluminum-copper alloy substrate, and then melting the aluminum-copper alloy substrate with silicon to obtain the aluminum-silicon-copper alloy. However, the aluminum-silicon-copper alloy obtained through this two-stage melting process has poor compositional uniformity, further affecting the performance of the sputtered thin film.

[0005] Therefore, it is of great significance to provide a method for preparing aluminum-silicon-copper ingots with good compositional uniformity and that can effectively avoid problems such as hot cracking and feather-like grains. Summary of the Invention

[0006] To address the above problems, the present invention aims to provide a method for preparing high-purity aluminum-silicon-copper ingots for target materials. Compared with the prior art, the aluminum-silicon-copper ingots obtained by the preparation method provided by the present invention are not only uniform in composition, but also free from hot cracks and feather-like grains.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for preparing high-purity aluminum-silicon-copper ingots for target materials, the method comprising the following steps:

[0009] (1) Melt the aluminum raw material to obtain molten aluminum;

[0010] (2) Put copper powder and silicon powder into an aluminum foil bag to obtain a powder bag, and add the powder bag to the aluminum liquid obtained in step (1) to obtain an aluminum-silicon-copper alloy liquid;

[0011] (3) The aluminum-silicon-copper alloy liquid obtained in step (2) is degassed and slag removed in sequence to obtain purified alloy liquid;

[0012] (4) The purified alloy liquid obtained in step (3) is sequentially cast and cooled to obtain the aluminum-silicon-copper ingot.

[0013] The method for preparing aluminum-silicon-copper ingots provided by this invention first involves melting aluminum raw materials to obtain molten aluminum. Then, copper powder and silicon powder, packaged in aluminum foil bags, are added to the molten aluminum. The aluminum foil bags melt first in the molten aluminum, and then the copper and silicon powders disperse in the molten aluminum. Compared with methods that directly add copper or silicon raw materials to molten aluminum, the preparation method provided by this invention can effectively promote the dispersion of aluminum, silicon, and copper, improve the uniformity of composition, and shorten the melting time.

[0014] In this invention, "high purity" in the high-purity aluminum-silicon-copper ingot refers to the fact that, apart from aluminum, silicon, and copper, the content of other elements is <5 ppm. The high-purity aluminum-silicon-copper ingot has an aluminum mass percentage content ≥98.5%, and a copper to silicon mass ratio of 1:(1.8-2.2).

[0015] In this invention, the purity of the aluminum raw material is ≥99.9995%.

[0016] Preferably, the melting temperature in step (1) is 740-760℃, for example, it can be 740℃, 742℃, 746℃, 748℃, 750℃, 752℃, 754℃, 756℃, 758℃ or 760℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the average particle size of the copper powder in step (2) is 10-20 μm, for example, it can be 10 μm, 12 μm, 14 μm, 16 μm, 18 μm or 20 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Preferably, the average particle size of the silicon powder is 10-20 μm, for example, it can be 10 μm, 12 μm, 14 μm, 16 μm, 18 μm or 20 μm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0019] In this invention, the purity of both the copper powder and the silicon powder is ≥99.9995%.

[0020] The present invention preferably controls the average particle size of copper powder and silicon powder within a specific range, which can further promote the dispersion of copper powder and silicon powder in aluminum liquid, thereby further improving the uniformity of composition.

[0021] Preferably, after copper powder and silicon powder are filled into the aluminum foil bag in step (2), a vacuum treatment is performed.

[0022] Preferably, the final vacuum level of the vacuuming process is (1-9)×10⁻⁶. -6 Pa, for example, could be 1×10 -6 Pa, 2×10 -6 Pa, 3×10 -6 Pa, 4×10 -6 Pa, 5×10 -6 Pa, 6×10 -6 Pa, 7×10 -6 Pa, 8×10 -6 Pa or 9×10 -6 Pa, but not limited to the listed values, applies to other unlisted values ​​within the range as well.

[0023] The present invention preferably employs vacuum treatment, which can further avoid uneven distribution of aluminum, silicon, and copper raw materials, thereby improving the uniformity of composition.

[0024] Preferably, the mass ratio of copper powder to silicon powder in the powder bag is 1:(1.8-2.2), for example, it can be 1:1.8, 1:1.9, 1:2, 1:2.1 or 1:2.2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] The present invention preferably controls the mass ratio of copper powder and silicon powder within a specific range, which can further promote the compositional uniformity of aluminum-silicon-copper ingots.

[0026] Preferably, the powder bag in step (2) is added to the molten aluminum in sequence through the first feeding, the second feeding and the third feeding. The ratio of the number of powder bags in the first feeding, the second feeding and the third feeding is 1:(2-4):(5-7), for example, it can be 1:2:5, 1:3:5, 1:4:5, 1:3:6, 1:3:7, 1:4:6 or 1:4:7, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] The present invention preferably controls the number of powder bags in the first, second and third feeding processes within a specific range, which can effectively shorten the smelting time while improving the compositional uniformity of aluminum-silicon-copper ingots.

[0028] Preferably, stirring is performed at intervals between each addition.

[0029] Preferably, the stirring time is 10-15 minutes, for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 15 minutes, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the degassing in step (3) includes: introducing argon gas into the aluminum-silicon-copper alloy liquid.

[0031] Preferably, the flow rate of the argon gas is 20-50 L / min, for example, it can be 20 L / min, 22 L / min, 24 L / min, 26 L / min, 28 L / min, 30 L / min, 32 L / min, 35 L / min, 38 L / min, 40 L / min, 42 L / min, 45 L / min, 48 L / min or 50 L / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0032] Preferably, the argon gas is introduced for 1-2 hours, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours or 2 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, the casting temperature in step (4) is 700-720℃, for example, it can be 700℃, 702℃, 704℃, 706℃, 708℃, 710℃, 712℃, 714℃, 716℃, 718℃ or 720℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, the flow rate of condensate in the cooling process in step (4) is 300-500 L / min, for example, it can be 300 L / min, 320 L / min, 340 L / min, 360 L / min, 380 L / min, 400 L / min, 420 L / min, 440 L / min, 460 L / min, 480 L / min or 500 L / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] Preferably, the temperature of the condensate in the cooling process is 10-15°C, for example, it can be 10°C, 11°C, 12°C, 13°C, 14°C or 15°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] The present invention preferably controls the temperature of the condensate within a specific range. On the one hand, this can increase the supercooling of the ingot during the cooling process, accelerate solidification, inhibit grain growth, refine grains, and thus suppress the generation of feather-like grains. On the other hand, it can reduce the stress between grains, reduce the tendency of intergranular hot cracks, and reduce the generation of cracks.

[0037] Preferably, the discharge rate of the cooled ingot in step (4) is 100-200 mm / min, for example, it can be 100 mm / min, 110 mm / min, 120 mm / min, 130 mm / min, 140 mm / min, 150 mm / min, 160 mm / min, 170 mm / min, 180 mm / min, 190 mm / min or 200 mm / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0038] As a preferred embodiment of the present invention, the preparation method includes the following steps:

[0039] (1) Melt the aluminum raw material at 740-760℃ to obtain molten aluminum;

[0040] (2) Pack the copper powder and silicon powder into an aluminum foil bag, and then vacuum process until the final vacuum degree is (1-9)×10. -6 Pa, to obtain a powder bag, wherein the average particle size of the copper powder is 10-20μm, the average particle size of the silicon powder is 10-20μm, the mass ratio of copper powder to silicon powder in the powder bag is 1:(1.8-2.2), the powder bag is added to the aluminum liquid in sequence through the first feeding, the second feeding and the third feeding, and the stirring is carried out for 10-15min between each adjacent feeding, the number ratio of powder bags in the first feeding, the second feeding and the third feeding is 1:(2-4):(5-7), to obtain aluminum-silicon-copper alloy liquid;

[0041] (3) Argon gas is introduced into the aluminum-silicon-copper alloy obtained in step (2) for 1-2 hours. The flow rate of argon gas is 20-50 L / min. Then, the slag is removed to obtain a purified alloy liquid.

[0042] (4) The purified alloy liquid obtained in step (3) is cast at 700-720℃ and then cooled. The flow rate of the cooling water is 300-500L / min and the temperature of the cooling water is 10-15℃. The discharge speed of the ingot after cooling is 100-200mm / min, and the aluminum-silicon-copper ingot is obtained.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The method for preparing high-purity aluminum-silicon-copper ingots provided by the present invention can fully promote the dispersion of aluminum-silicon-copper, improve the uniformity of composition, and shorten the smelting time. The measured content of copper element is less than 0.01% different from the mass percentage of copper powder in the raw material.

[0045] (2) The method for preparing high-purity aluminum-silicon-copper ingots provided by the present invention can suppress grain growth in the ingot, refine the grains, and thus suppress the generation of feather-like grains; at the same time, it reduces the stress between grains, reduces the tendency of intergranular hot cracks, and thus reduces crack generation. Detailed Implementation

[0046] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0047] Example 1

[0048] This embodiment provides a method for preparing high-purity aluminum-silicon-copper ingots for target materials, the preparation method comprising the following steps:

[0049] (1) The aluminum raw material (purity 5N5) is melted at 750℃ to obtain aluminum liquid;

[0050] (2) Pack copper powder and silicon powder (both with a purity of 5N5) into an aluminum foil bag, and then vacuum process until the final vacuum degree is 5×10. -6 Pa, to obtain a powder bag, wherein the average particle size of the copper powder is 15μm, the average particle size of the silicon powder is 15μm, the mass ratio of copper powder to silicon powder in the powder bag is 1:2, the powder bag is added to the aluminum liquid in sequence through the first feeding, the second feeding and the third feeding, and the stirring is carried out for 12 minutes between each adjacent feeding, the number ratio of powder bags in the first feeding, the second feeding and the third feeding is 1:3:6, to obtain aluminum-silicon-copper alloy liquid;

[0051] Based on the sum of the masses of aluminum raw materials, copper powder, and silicon powder, aluminum raw materials account for 98.5% of the mass, copper powder accounts for 0.50% of the mass, and silicon powder accounts for 1.0% of the mass.

[0052] (3) Argon gas is introduced into the aluminum-silicon-copper alloy obtained in step (2) for 1.5 hours at a flow rate of 35 L / min, and then slag is removed to obtain a purified alloy liquid.

[0053] (4) The purified alloy liquid obtained in step (3) is cast at 710°C and then cooled. The flow rate of the cooling water is 400 L / min and the temperature of the cooling water is 12°C. The discharge speed of the ingot after cooling is 150 mm / min, and the aluminum-silicon-copper ingot is obtained.

[0054] Example 2

[0055] This embodiment provides a method for preparing high-purity aluminum-silicon-copper ingots for target materials, the preparation method comprising the following steps:

[0056] (1) The aluminum raw material (purity 5N5) is melted at 740℃ to obtain molten aluminum;

[0057] (2) Pack copper powder and silicon powder (both with a purity of 5N5) into an aluminum foil bag, and then vacuum process them until the final vacuum degree is 9×10. -6 Pa, to obtain a powder bag, wherein the average particle size of the copper powder is 10 μm, the average particle size of the silicon powder is 10 μm, and the mass ratio of copper powder to silicon powder in the powder bag is 1:1.8. The powder bag is added to the aluminum liquid in sequence through the first feeding, the second feeding and the third feeding, and the stirring is carried out for 10 minutes between each adjacent feeding. The ratio of the number of powder bags in the first feeding, the second feeding and the third feeding is 1:2:5, to obtain an aluminum-silicon-copper alloy liquid;

[0058] Based on the sum of the masses of aluminum raw materials, copper powder, and silicon powder, aluminum raw materials account for 98.5% of the mass, copper powder accounts for 0.53% of the mass, and silicon powder accounts for 0.97% of the mass.

[0059] (3) Argon gas is introduced into the aluminum-silicon-copper alloy obtained in step (2) for 1 hour at a flow rate of 50 L / min, and then slag is removed to obtain a purified alloy liquid.

[0060] (4) The purified alloy liquid obtained in step (3) is cast at 700°C and then cooled. The flow rate of the cooling water is 500 L / min and the temperature of the cooling water is 10°C. The discharge speed of the ingot after cooling is 200 mm / min, and the aluminum-silicon-copper ingot is obtained.

[0061] Example 3

[0062] This embodiment provides a method for preparing high-purity aluminum-silicon-copper ingots for target materials, the preparation method comprising the following steps:

[0063] (1) The aluminum raw material (purity 5N5) is melted at 760℃ to obtain aluminum liquid;

[0064] (2) Pack copper powder and silicon powder (both with a purity of 5N5) into an aluminum foil bag, and then vacuum process them until the final vacuum degree is 1×10. -6Pa, to obtain a powder bag, wherein the average particle size of the copper powder is 20 μm, the average particle size of the silicon powder is 20 μm, and the mass ratio of copper powder to silicon powder in the powder bag is 1:2.2. The powder bag is added to the aluminum liquid in sequence through the first feeding, the second feeding and the third feeding, and the stirring is carried out for 15 minutes between each adjacent feeding. The ratio of the number of powder bags in the first feeding, the second feeding and the third feeding is 1:4:7, to obtain an aluminum-silicon-copper alloy liquid;

[0065] Based on the sum of the masses of aluminum raw materials, copper powder, and silicon powder, aluminum raw materials account for 98.5% of the mass, copper powder accounts for 0.47% of the mass, and silicon powder accounts for 1.03% of the mass.

[0066] (3) Argon gas is introduced into the aluminum-silicon-copper alloy obtained in step (2) for 2 hours at a flow rate of 20 L / min. Then, the slag is removed to obtain a purified alloy liquid.

[0067] (4) The purified alloy liquid obtained in step (3) is cast at 720°C and then cooled. The flow rate of the cooling water is 300L / min and the temperature of the cooling water is 15°C. The discharge speed of the ingot after cooling is 100mm / min, and the aluminum-silicon-copper ingot is obtained.

[0068] Example 4

[0069] This embodiment provides a method for preparing high-purity aluminum-silicon-copper ingots for target materials. The only difference from Embodiment 1 is that the powder bag is added to the molten aluminum at once.

[0070] Example 5

[0071] This embodiment provides a method for preparing high-purity aluminum-silicon-copper ingots for target materials. The only difference from Embodiment 1 is that after copper powder and silicon powder are put into the aluminum foil bag, vacuum treatment is not performed.

[0072] Example 6

[0073] This embodiment provides a method for preparing high-purity aluminum-silicon-copper ingots for target materials. The only difference from Embodiment 1 is that the temperature of the condensate during cooling is 5°C.

[0074] Example 7

[0075] This embodiment provides a method for preparing high-purity aluminum-silicon-copper ingots for target materials. The only difference from Embodiment 1 is that the temperature of the condensate during cooling is 20°C.

[0076] Comparative Example 1

[0077] This comparative example provides a method for preparing a high-purity aluminum-silicon-copper ingot for a target material. The only difference from Example 1 is that step (2) is replaced by adding copper powder and silicon powder directly to the aluminum liquid obtained in step (1) to obtain an aluminum-silicon-copper alloy liquid.

[0078] Ultrasonic testing was performed on the aluminum-silicon-copper ingots prepared in Examples 1-7 and Comparative Example 1, and the results are shown in Table 1.

[0079] The aluminum-silicon-copper ingots prepared in Examples 1-7 and Comparative Example 1 were machined, and the presence of feather-like grains on the machined surface was observed. The results are shown in Table 1.

[0080] The copper content of the aluminum-silicon-copper ingots prepared in Examples 1-7 and Comparative Example 1 was determined. The determination method was as follows: samples were taken from different parts of the aluminum-silicon-copper ingots in sequence, and the copper content was determined by ICP-OES detection technology. The results are shown in Table 1.

[0081] Table 1

[0082]

[0083]

[0084] The following points can be observed from Table 1:

[0085] (1) As can be seen from the data of Examples 1-7, the measured content of copper element is less than 0.01% different from the mass percentage of copper powder in the raw material, indicating that the composition is uniform and that the aluminum-silicon-copper ingot has no cracks and feather-like grains under the better conditions.

[0086] (2) A comprehensive comparison of the data from Example 4 and Example 1 shows that the only difference between Example 4 and Example 1 is that the powder bag is added to the aluminum liquid all at once. The measured content of copper in Example 4 fluctuates more than that in Example 1. This indicates that adding the powder bag all at once results in poor composition uniformity and the alloy composition is not easy to diffuse evenly. The present invention adopts the method of adding the powder bag in stages, which can further improve the composition uniformity of the ingot.

[0087] (3) A comprehensive comparison of the data from Example 5 and Example 1 shows that the only difference between Example 5 and Example 1 is that after copper powder and silicon powder are placed in the aluminum foil bag, no vacuum treatment is performed. The measured copper content in Example 5 is lower than that in Example 1. This indicates that not performing vacuum treatment may result in a lower density of the powder package, making it difficult to sink into the molten aluminum, leading to oxidation of some powder and loss. Therefore, this invention preferably performs vacuum treatment, which can further ensure the composition content in the ingot and avoid the introduction of oxides.

[0088] (4) A comprehensive comparison of the data from Examples 6-7 and Example 1 shows that the temperature of the condensate in Example 1 is 12°C, compared to 5°C and 20°C in Examples 6-7, respectively. In Example 6, the water temperature is too low, which can cause ingot cracks. In Example 7, the water temperature is too high, which can cause feather-like grains. This indicates that the present invention preferably controls the temperature of the condensate, which can effectively prevent ingot cracks and feather-like grains.

[0089] (5) By comparing the data of Example 1 and Comparative Example 1, it can be seen that the difference between Comparative Example 1 and Example 1 is that step (2) is replaced by adding copper powder and silicon powder directly to the aluminum liquid obtained in step (1) to obtain aluminum-silicon-copper alloy liquid. The measured content of copper element in Comparative Example 1 fluctuates more than that in Example 1, which shows that the preparation method provided by the present invention can effectively promote the uniformity of aluminum-silicon-copper composition.

[0090] In summary, the method for preparing high-purity aluminum-silicon-copper ingots provided by this invention can effectively promote the dispersion of aluminum-silicon-copper, improve the uniformity of composition, and avoid the generation of cracks and feather-like grains.

[0091] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing high-purity aluminum-silicon-copper ingots for target materials, characterized in that, The preparation method includes the following steps: (1) Melt the aluminum raw material to obtain molten aluminum; (2) Copper powder and silicon powder are packed into aluminum foil bags to obtain powder bags. The powder bags are added to the aluminum liquid obtained in step (1) to obtain aluminum-silicon-copper alloy liquid. After the aluminum foil bag is filled with copper powder and silicon powder, it is vacuum-sealed. The powder bags are added to the molten aluminum in sequence through the first feeding, the second feeding and the third feeding, and the ratio of the number of powder bags in the first feeding, the second feeding and the third feeding is 1:(2-4):(5-7); (3) The aluminum-silicon-copper alloy liquid obtained in step (2) is degassed and slag removed in sequence to obtain purified alloy liquid; (4) The purified alloy liquid obtained in step (3) is sequentially cast and cooled to obtain the aluminum-silicon-copper ingot; The flow rate of the condensate in the cooling process is 300-500 L / min; the temperature of the condensate in the cooling process is 10-15℃.

2. The preparation method according to claim 1, characterized in that, The melting temperature in step (1) is 740-760℃.

3. The preparation method according to claim 1, characterized in that, The average particle size of the copper powder in step (2) is 10-20 μm.

4. The preparation method according to claim 1, characterized in that, The average particle size of the silicon powder is 10-20 μm.

5. The preparation method according to claim 1, characterized in that, The final vacuum level of the vacuuming process in step (2) is (1-9)×10⁻⁶. -6 Pa.

6. The preparation method according to claim 1, characterized in that, The mass ratio of copper powder to silicon powder in the powder bag is 1:(1.8-2.2).

7. The preparation method according to claim 1, characterized in that, Step (2) Stir at the intervals between each addition.

8. The preparation method according to claim 7, characterized in that, The stirring time is 10-15 minutes.

9. The preparation method according to claim 1, characterized in that, The degassing step (3) includes: introducing argon gas into the aluminum-silicon-copper alloy liquid.

10. The preparation method according to claim 9, characterized in that, The flow rate of the argon gas is 20-50 L / min.

11. The preparation method according to claim 9, characterized in that, The argon gas is introduced for 1-2 hours.

12. The preparation method according to claim 1, characterized in that, The casting temperature in step (4) is 700-720℃.

13. The preparation method according to claim 1, characterized in that, The discharge rate of the cooled ingot in step (4) is 100-200 mm / min.

14. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) Melt the aluminum raw material at 740-760℃ to obtain molten aluminum; (2) Pack the copper powder and silicon powder into an aluminum foil bag, and then vacuum process it until the final vacuum degree is (1-9)×10. -6 Pa, to obtain a powder bag, wherein the average particle size of the copper powder is 10-20μm, the average particle size of the silicon powder is 10-20μm, the mass ratio of copper powder to silicon powder in the powder bag is 1:(1.8-2.2), the powder bag is added to the aluminum liquid in sequence through the first feeding, the second feeding and the third feeding, and the stirring is carried out for 10-15min between each adjacent feeding, the number ratio of powder bags in the first feeding, the second feeding and the third feeding is 1:(2-4):(5-7), to obtain aluminum-silicon-copper alloy liquid; (3) Argon gas is introduced into the aluminum-silicon-copper alloy obtained in step (2) for 1-2 hours. The flow rate of argon gas is 20-50 L / min. Then, the slag is removed to obtain a purified alloy liquid. (4) The purified alloy liquid obtained in step (3) is cast at 700-720℃ and then cooled. The flow rate of the cooling water is 300-500L / min and the temperature of the cooling water is 10-15℃. The discharge speed of the ingot after cooling is 100-200mm / min, and the aluminum-silicon-copper ingot is obtained.

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